Referring to FIG. 1, a conventional projector is shown to include an outer casing 2 provided with a projection lens for projecting an image onto a screen. The outer casing 2 is further provided with an elevating device 6 for adjusting an inclination angle of a front end of the outer casing 2 with respect to a support surface. The outer casing 2 has a front wall formed with a front opening 10 and a bottom wall formed with a lower opening 4.
Referring to FIGS. 1 and 2, the elevating device 6 includes a base plate 18, a generally rectangular push member 602, a partition 1802, an urging member 28, a rack member 26. The base plate 18 is disposed securely on the bottom wall of the outer casing 2, and is formed with a rack aperture 19 in aligned with the lowering opening 4. The push member 602 is disposed slidably on the base plate 18 around the rack aperture 19, and has a press button 20 protruding outwardly from the front wall via the front opening 10. The push member 602 further has a front portion integrally formed with the press button 20, a rear portion 24 formed with a row of teeth 2402, and an intermediate portion 22 interconnecting the front and rear portions 24. The partition 1802 is fixed to the base plate 18 transverse to the rack aperture 19, and extends upwardly from the base plate 18. The rack member 26 is disposed uprightly within the rack aperture 19 in the base plate 18 behind the partition 1802. The urging member 28 is disposed between the partition 1802 and the front portion of the push member 20, and urges the push member 20 in the forward direction with respect to the base plate 18, thereby resulting in engagement between the rack member 26 and one of the teeth 2402 on the rear portion 24 of the push member 602. Preferably, a support pad 8, for example a soft pad is fixed to a lower end of the rack member 26 to permit resting of the rack member 26 on the support surface.
When it is desired to adjust the inclination angle of the outer casing 2 with respect to the support surface, the press button 20 is pressed inwardly relative to the outer casing 2 so as to result in rearward movement of the push member 602 relative to the base plate 18, which in turn, results in disengagement of the rack member 26 from the rear portion 24 of the push-member 602. Under this condition, the lower end of the rack member 26 protrudes outwardly from the outer casing 2 via the lower opening 4 by virtue of gravity thereof. To retract the rack member 26 into the outer casing 2, the same can be manually pushed upward against the urging force of the urging member 28.
The aforesaid rack member 26 though can adjust the inclination angle of the outer casing 2 with respect to the support surface, the inclination adjustment thereof is not ideal due to the compact size of the outer casing 2. Increase in the longitudinal length of the rack member 26 may result in a larger dimension of the outer casing 2. It is against trend of manufacturers to produce the conventional projector in the compact size.